1. Field of the Invention
The present invention relates to plug-in connectors for connecting printed circuit boards to external circuitry, and in particular to an improved spring contact for such connectors which permits assembly of connector systems of selected length and minimizes or eliminates manual back panel wiring.
2. Description of the Prior Art
Plug-in connectors for releasably receiving an edge of a circuit board having printed terminal elements thereon are well known in the art. Such connectors generally consist of a plastic housing containing a plurality of spring contact strips which individually receive a circuit board terminal therebetween and retain same in place by means of spring tension. Such a plug-in connector is known, for example, from German AS No. 2,300,485 as well as "The Universal Plug-in Connector Family for Printed Circuit Boards According to DIN 41 612", Verlag Market and Technik, Dirk Hesse, 1979 and DIN 41 613.
Such conventional plug-in connectors utilize the spring contact as a bridge between the printed circuit and a wiring field which is connected to pins extending from the rear of the connector at a back panel in a number of rows. Connection can be made to the back panel pins in any manner known to those skilled in wire connection technology such as, for example, wire wrap, clamping, crimping, and soldering. Regardless of the wire connection technique employed, however, connection of the individual pins to the wiring field involves a substantial outlay in time inasmuch as such connection must generally be undertaken manually on a pin-to-pin basis.
Moreover, once connected, the conventional pin structure does not easily allow for modification of or addition to the wire connections should changes be made on the circuit board with which the connector is to be utilized. This disadvantage is particularly acute when subassembly circuit boards are subsequently augmented by additional plug-in units also carried on printed circuit boards.